In typical use, a portable device may be powered by a battery having a fixed capacity. The current draw by the portable device from the battery may not be constant, however. Many modern devices implement power management schemes whereby components of the device that are not being used are moved to a lower power state to reduce device power consumption and increase battery life. As some examples, the portable device may reduce its power consumption by deactivating the screen when the screen is not being used, reducing the brightness of a backlight according to ambient lighting, turning off one or more processors when they are not in use and deactivating network components when network facilities are not required.
Battery life is an important consideration for battery-powered mobile devices. For example, many models of smartphone and tablet computer advertise estimated battery life information. However, a user may not necessarily observe the advertised battery life. This may be due to various factors, one of which being that applications installed on the device may make excessive use of device resources when the device is idle or not actively being used, negatively affecting the battery life. However, users may be unaware of the cause of the battery drain, and may become frustrated with their devices.